I defended my friend's partner, and although I believe I made the right choice, I can't help but dislike how it feels.

I (22F) have a close male friend, J (22M), who has been in a relationship with N (22F) for the past few months. While I’ve known N for a few years, we’ve never been close, merely acquaintances within the same social group. Recently, during one of our conversations, I noticed J seemed a bit down. I suggested we meet up to talk. He opened up about feeling emotionally neglected in his relationship, sharing how he often feels like he’s giving endlessly without receiving comfort or understanding in return. It truly pained me to see him struggle, so I gave him a hug. He held onto me longer than I expected, and I could tell he was on the verge of tears. When we met again the following week, he shared that our time together had provided him with great comfort and that I was the only person he felt safe confiding in. While we were chatting on his bed, we ended up cuddling. However, I mentioned that we might be crossing a boundary and suggested we keep some physical distance. He agreed and moved away immediately. I believe this was the right decision; I wouldn’t want to be in a situation where my partner was cuddling with their best friend if I were in a relationship. Still, I can’t shake the feeling that I might be overthinking it, especially since I’ve been cheated on before. In the back of my mind, I also wrestle with the notion that it feels unfair for me to uphold a “girls support girls” mentality when N isn’t treating J well. I’m reminded of how the girls my ex cheated on me with never spoke up for me, even though they knew me. Did I make the right choice?